1. Field of the Invention
The present invention is directed toward a pad assembly for automobile body refinishing, and more particularly, to a quick release connector used to connect a single or dual-sided buffing, polishing or abrasive pad assembly to a power tool.
2. Description of Related Art
Buffing refers to the application of a chemical or compound to a surface using a buffing pad. In the automotive detailing industry, for example, buffing is used to repair, refinish or polish the exterior surfaces of automobiles. Buffing can be done by hand, however, professionals and consumers alike prefer to use buffing pads with power buffers. A power buffer can be pneumatic, in which the power is supplied by an air compressor, or motorized, in which the power is supplied by an electric motor. A motorized power buffer is a hand-held tool having a buffing pad attached to a spindle that extends from the electric motor. The motor spins the buffing pad and thus results in faster performance, while reducing fatigue on the operator. It also allows the operator to get optimum finishing effects as compared to buffing by hand.
There are two types of motorized power buffers, including high-speed rotary buffers and dual-action or random orbital buffers. The main difference between the two relates to the direction of the rotation of the buffing pad assembly, which in turn produces different results. High-speed buffers provide a circular motion, spinning at very high continuous revolutions per minute (RPMs) and can have either one or two buffing pads attached to the motor. For example, a dual-head buffer is a high-speed rotary buffer having two buffing pads attached to the motor, adjacent to each other. Dual-action or random-orbital buffers turn in a combined circular and orbital motion, at varying speeds. The continuous revolutions of either type of buffer causes friction on contact with the surface producing heat, that when combined with a compound alters the surface of the automobile. Power buffers are used for various purposes, including repairing damages to surfaces or for different finishing effects. The buffing pads are usually circular, are made in varying sizes and are made of various materials, such as natural wool, synthetic fibers, a blend of wool and synthetic fibers or open or closed cell synthetic foam.
Because the power buffer spins the buffing pad at a high rotational rate, the type of motion, whether it be circular, orbital or both, is integral to the desired polishing and/or waxing effect. Consequently, effective performance of the power buffer relates to the interaction between the compound, the buffing pad and the power buffer, and more particularly the connection between the buffing pad assembly and the power buffer, which directly effects the rotation. If any one of these fail, the results will be less than desirable. An uneven application of the compound can cause unsightly swirls on the surface that can only be removed by a polisher and not by hand, if at all. Certain compounds and pads, e.g., wool pads, are inherently designed to cut into the paint to repair damages. An uneven application or a faulty assembly can cause the wool pad to chip away at the surface and cause more damage. Thus, a proper connection between the buffing pad and the power buffer is critical to achieving desired results.
Buffing pads can be either single-sided or dual-sided. The single-sided pad is affixed to a backing plate made of plastic, metal or other rigid material. A dual-sided buffing pad includes a central backing plate that is sandwiched between two pads. Dual-sided pads are advantageous since they can be flipped over to provide continuous use. Also, dual-sided pads do not have an exposed backing plate that may contact the automobile surface and cause damage.
There are three known ways to affix the buffing pad to the spindle of the power buffer. A first way is to affix the buffing pad to a backing plate using a bolt. The backing plate has a round, non-threaded center hole that is sized to slide over the spindle. The buffing pad also has a center hole that is aligned with the center hole of the backing plate when the buffing pad is placed on the backing plate, with the threaded end of the spindle extending though both center holes. A metal nut is used to engage the threaded end of the spindle and affix the buffing pad and backing plate to the spindle. High-speed buffers typically have a lock button for the spindle shaft that prevents the spindle from rotating. Hence, with the spindle shaft locked, it is relatively easy to manually tighten the nut to affix the buffing pad and backing plate to the spindle, as well as to manually loosen the nut to remove the buffing pad and backing plate from the spindle. A drawback of this approach is that it is time consuming and cumbersome to change buffing pads during use. Another drawback is that this approach cannot be used with double-sided buffing pads. Notwithstanding these drawbacks, bolt-on buffing pads are widely used due to their relatively low cost.
A second attachment method is to affix the buffing pad to the backing plate uses a hook and loop (e.g., Velcro®) fastener. The backing plate is provided with a threaded metal socket molded into the back surface and hook material attached to the front surface. The threaded metal socket enables the backing plate to be screwed directly onto the threaded end of the spindle shaft. The buffing pad has loop material attached to its back surface, enabling the buffing pad to be affixed to the backing plate by simply pressing the buffing pad and the backing plate together. The hook and loop attachment facilitates ease of attachment to and removal of the buffing pad from the backing plate. As with the bolt-on method, the hook and loop fastening method cannot be used with double-sided buffing pads.
A third type of attachment method used exclusively with double-sided pads includes an adapter having a socket with female threads at one end and male threads at the other end. The female threads enables the adapter to be threaded onto the spindle. The male threads attach to a plastic plate that is sandwiched between two buffing pads bonded back-to-back. The plate includes a central socket having threads that engage the male end of the adapter. The adapter remains attached to the spindle, and the buffing pad is attached to the adapter by screwing the entire buffing pad assembly onto the male end of the adapter. When the buffing pad surface becomes spent, the entire pad assembly is unscrewed and either flipped over or replaced entirely. A drawback of this method is that the high speed rotation of the spindle tends to further tighten the male end of the adapter onto the buffing pad, making it difficult to manually remove the buffing pad from the adapter. Another drawback is that the plastic plate with the double-sided pad is necessarily disposed of when both sides of the pad are spent, thereby increasing the replacement cost of the buffing pad.
To overcome some of these drawbacks, it is known to attach the dual-sided buffing pad assembly to the power buffer using an adapter or connector that provides a quick release mechanism. Such a quick release mechanism is advantageous in that it allows the pad to be easily detached from the power buffer and flipped over to continue buffing with the unused side, without requiring any special tools. This saves time in retrieving another pad and enables the operator to continue working with minimal interruption. The commercially known type of quick release mechanism connects the buffing pad assembly to the power buffer using a cylindrical shaped metal connector. One end of the connector has a threaded bore that engages the spindle of the power buffer. The other end has a hexagonal shaped head that engages a correspondingly shaped socket formed at the center of the central plate. The head further includes a plurality of protruding balls that snap into a recess formed in the socket to thereby provide a firm connection between the power buffer and buffing pad. The connector includes a release mechanism that causes the protruding balls to retract in order to facilitate removal of the buffing pad from the connector head. A button located on the connector head enables manual operation of the release mechanism. The release mechanism further includes an internal spring within the body of the connector that biases the protruding balls outward. The connector further includes an adjusting screw that serves to vary the tension applied by the spring onto the protruding balls.
Notwithstanding the advantages of the known quick release mechanism, there are also many practical drawbacks. Since the connector body is typically formed of a high strength material, such as metal, the hexagonal shaped head is difficult and hence expensive to manufacture, particularly in comparison to a simple, round head. Moreover, it is difficult to align the hexagonal connector head onto the corresponding hexagonal socket. The buffing pad impedes a clear view of the socket and the operator will typically fumble with the device for a while before getting the connector head and socket aligned together.
Due to the inconsistency in manufacturing tolerances of the plastic socket contained within the dual-sided pad, the quality of the fit between the connector body head and the socket will vary from unit-to-unit. In some cases, the head will fit snugly within the socket, while in other cases the head will fit loosely within the socket. After continued use, the plastic socket at the center of the backing plate tends to wear out, providing an even looser fit with the hexagonal shaped head. If the connector head does not maintain a snug fit with the socket, the buffing pad will wobble during operation. This causes an undesirable vibration that effects the rotation of the buffing pad, thereby causing poor application of the compound. The vibration also contributes to operator fatigue, and thereby reduces the productivity of the automotive detailing operation.
Often, operators of the power buffer will buff a portion of the automobile surface using the back side of the dual-sided pad, such as to reach an edge of a wheel well. This exerts force on the buffing pad assembly that could cause it to inadvertently pop off of the connector during use, potentially resulting in injury to the operator and/or damage to the automobile surface. To avoid this condition, the operator may be tempted to increase the tension on the internal spring by tightening the adjusting screw in order to thereby achieve a tighter fit; however, this makes it more difficult to use the quick release mechanism to remove the buffing pad when it is spent.
Another drawback with the known quick release mechanism is that the compound used to buff the surface tends to collect in the socket at the center of the plate. The compound gets into the body of the connector and impedes retraction of the protruding balls. As a result, it becomes difficult to remove the buffing pad assembly from the connector. Even under normal conditions without the presence of compound in the body of the connector, the factory setting of the spring tension applied by the release mechanism can require significant pressure by the operator to overcome and thereby compress the spring.
Yet another drawback of the known quick release mechanism is that the connector body is relatively long in comparison to the traditional adapter due to the inclusion of the release mechanism within the body of the connector. This relatively longer distance between the buffer and the pad can be disorienting for the operator that is already accustomed to a certain shorter distance. This tends to further exacerbate operator fatigue and result in an uneven application to the automotive surface.
For each of the foregoing reasons, a need exists for an improved quick release mechanism that enables attachment between a single or dual-sided buffing pad (or the like) and a power tool (e.g., a power buffer) without interfering with the overall function of the power tool and without including any moving parts, while otherwise maintaining the overall convenience and ease of use of the quick release feature.